Currently, with development of communications technologies, a battery level of a mobile terminal such as a mobile phone, a mobile broadband router, or a tablet computer becomes higher, where battery capacities of the mobile phone and the mobile broadband router exceed 3000 milliampere-hours (mAh), and a battery capacity of the tablet computer exceeds 6000 mAh, which makes it possible for the mobile terminal to be used as a mobile power supply source to supply power to another device. After an existing mobile terminal device is shut down, if a to-be-charged device needs to be charged, either of the following two methods may be selected to make a mobile power supply terminal supply power to the to-be-charged device.
A first method is a user manually turns on the mobile device, and after being turned on, the device is configured to trigger, using a man-machine interface of the terminal, the terminal to supply power outwards.
A second method is the user manually turns on the mobile device, and after the mobile device is turned on, a ground point of a charging interface of the to-be-charged device pulls down an electrical level of a power supply trigger end of the mobile device, thereby triggering the mobile device to supply power outwards.
The following problems exist when the foregoing two methods are used to charge the to-be-charged device in a shutdown mode of the terminal.
1: The mobile power supply terminal must first be completely turned on according to a normal turn-on mode. The startup time is long, and the mobile power supply terminal cannot be charged quickly.
2: The mobile power supply terminal is completely turned on according to the normal turn-on mode, and many power-consuming functional modules of the mobile power supply terminal are turned on. For example, when the mobile terminal is a tablet computer, after the tablet computer is completely started, at least functions such as a backlight, a display screen, a network interface card, and a firewall are enabled; for another example, when the mobile terminal is a mobile phone, after the mobile phone is turned on, a communications functional module is automatically turned on. Since these hardware or software modules are all energy-consuming modules, the terminal has large power consumption when the terminal charges an external device, and therefore, the energy consumption is large.
3: The mobile terminal is in a complete turn-on state after being normally turned on, charges an external device and also consumes electricity itself, which causes a large current in a power supply source, and high temperature of the battery. If this lasts for a long time, problems such as a short life of the battery and poor stability may be caused.
In addition, in a startup state, the mobile terminal supplies power outwards, and also turns on another functional module, for example, a functional unit for implementing a function other than power supply, such as a communications unit or a video display functional unit, which causes a large current in the power supply source, and unstable power supply. It should be ensured that power supply meets requirements and a communications data service in another communications function is not limited.